Sleep disturbances are increasingly recognized as early features of Alzheimer’s disease (AD) neuropathology. Specifically, spontaneous arousals during sleep have been associated with the burden of Amyloid beta in the brain of healthy late middle-aged individuals. However, it remains unclear whether the heterogeneity of arousals relates to genetic risk for AD in younger adults or to cognitive change later in life.
In this study, researchers evaluated the association between sleep arousals, polygenic risk scores (PRS) for AD, and cognitive performance and change in healthy young and late-middle-aged individuals. The study involved 453 younger individuals (average age 22 years) and 87 late middle-aged individuals (average age 59.3 years), with a focus on the prevalence and types of spontaneous arousals classified using in-lab EEG sleep recordings.
The findings revealed that the prevalence of arousals associated with sleep stage transitions was higher in late middle-aged individuals compared to younger individuals. Notably, in late middle-aged individuals, transition arousals with muscle tone increases correlated with lower AD-PRS, better attentional performance, and lower memory change over follow-ups. In contrast, transition arousals without muscle tone increases were linked to higher AD-PRS, poorer baseline attention, and greater memory change across follow-up periods.
The study concludes that the heterogeneity in spontaneous arousals during sleep may reflect their physiological intensity or underlying neural activation, indicating vulnerability to AD in late middle-aged individuals. The findings suggest that identifying early markers of neurodegenerative risk could be possible through the analysis of sleep arousals.
What this study does not show
This study does not establish a direct causal relationship between sleep arousals and the development of Alzheimer’s disease, nor does it provide evidence of clinical utility in predicting individual outcomes based on sleep arousal patterns.
Evidence scorecard
- Analytic validity: Established
- Clinical validity: Partial
- Clinical utility: Not established
The evidence is based on primary research involving human participants.